Watershed Management Research
Year:2019 | Volume:32 | Issue:1 (122)|Papers Count:8

The catastrophic flooding of Shiraz on 25 March 2019 downstream of the Qurâ n Gate, which resulted in the mournful death of 22 and untold financial damages, and also numerous deluges later in many Iranian provinces with upwards of 73 deaths due to drowning or collapse of residences, urges the decision-makers to consider every single stretch of land as a catchment and plan the infrastructures on it accordingly. This task requires planning from the perspective of seasoned watershed managers. Sustainable management of marginal drylands, which form some 90% of the present day Iranian Plateau, should be the most important objective of urban and rural developers if the safety and security of their occupants are expected. The utmost objective of watershed management in the 1960s was soil conservation upstream of the large dams constructed with the technical know-how of international experts. This was done to elongate the economic life of the dams and their appurtenances. It is fortunate that the new crop of watershed mangers is intent on taking an integrated approach toward solving problems. They, therefor, contemplates technical practicability, environmental soundness, financial feasibility and social acceptability in planning watershed rehabilitation by being up-to-date on the latest proven results published in scientific journals. Obviously, a paradigm shift in watershed management strategies seems necessary in the context of climate change, particularly with respect to unprecedented droughts and downpours. The question is: How to plan?

A sediment fingerprinting method was applied to identify and quantify terrestrial sediment source contributions to coastal sand dunes at the outlet of the Jagin watershed, east of Jask, the Province of Hormozgan. Sampling comprised of 20 sediment samples from coastal sands and 62 samples from potential upstream terrestrial sources. Concentration of 49 geochemical elements in the sediment and source samples were measured using the ICP-OES technique. A three-stage statistical procedure was used to identify final composite fingerprints for source discrimination, and this comprised of a range test for tracer conservation, the Kruskal-Wallis H-test for confirming the discriminatory efficacy of the individual properties and the stepwise discriminant function analysis (DFA) for selecting a tracer shortlist (i. e., composite signature). The final composite fingerprint selected by the stepwise DFA comprised of Cu, Th, Be, Al, La, Mg and Fe. Using this signature, the overall average mean relative contributions from the Quaternary, Oligocene-Miocene, Miocene and Paleocene geological units were estimated at 5%, 5%, 10% and 80%, respectively. The Paleocene geological unit was identified as the dominant spatial source for 16 of the 20 sediment samples. Therefore, wind erosion control for the benefit of coastal deserts, and especially the Makran region, needs to target upstream watersheds with the Paleocene outcrops. Overall, Paleocene age deposits (including multi-ophiolite sandstone, siltstone, mudstone, and minor conglomerate) was recognized as the main source for 16 sediment samples. Therefore, for controling water erosion in upstream and mitigating effects of wind erosion in downstream, management activities must focus on this source.

It is essential for the proper management of lakes to know physical and chemical factors in their different parts and in different times of the year. This project aims to investigate basic limnology of physical and chemical factors in Salman-Farsi Reservoir, Ghir County, the Province of Fars. Seasonal samplings were carried out in 2007 in 27 stations. Analysis of variance was used to compare seasonal variations of the studied factors. The annual means of the studied items were as following: water temperature (22. 6° C), dissolved oxygen (8. 2 ppm), carbon dioxide (0. 9 ppm), pH (7. 8), transparency (352 cm), electrical conductivity (874 µ S/cm), total dissolved solids (570 ppm), total hardness (630 ppm), nitrite ion (0. 02 ppm), nitrate ion (0. 8 ppm), ammonia (0. 04 ppm), phosphate ion (0. 4 ppm), biochemical oxygen demand (3. 8 ppm), and chemical oxygen demand (19. 3 ppm). Compari-son of the results with the drinking water standards showed that the lake water is suitable regarding pH, electrical conductivity, total dissolved solids, ammonia, nitrite, and nitrate concentrations, but its total hardness was slightly higher than the permitted values. Temperature, pH, dissolved oxygen, electrical conductivity, total dissolved solids, carbon dioxide, nitrite, nitrate, concentrations as well as biochemical oxygen demand showed acceptable levels all over the lake as compared with water quality standards for warm-water aquaculture. Chemical oxygen demand measures were at proper levels in the lacustrine and transitional sections, but slightly higher than this level in the riverine areas. Ammonia levels were appropriate in the lacustrine but moderately higher in the riverine and transitional sections. Transparency, total hardness, and phosphate ion concentration were much higher than the standard levels of warm-water aquaculture.

Carbon sequestration (CS) in soils is a phenomenon consistent with the principles of sustainable development. Further, it is a vital solution for reducing the atmospheric CO2 and other GHGs. To identify the role of spate irrigation (SI) of afforested plots and rangeland in CS, 36 soil samples were collected from the 0– 30 cm top soil in different spate-irrigated and control treatments in November 2017. Organic carbon (OC) was measured by the standard laboratory procedures, and then converted to the sequestered soil carbon (SOC). The data were analyzed using the randomized complete block design benefitting from the SAS software. The means were compared with the Duncan test at P<0. 05 level. The results of analysis of variance showed that the effect of 36 years of flood spreading on different vegetative covers was significant for OC, and SOC at the P<0. 01 level. The soil under the dense eucalyptus forest had sequestered 44. 2 tons/ha of carbon after 35 years of operation above the unirrigated control; this is equivalent to 162. 12 tons of CO2; this amounts to 4. 6 tons of CO2 per year on average. The total income from the carbon rent of the dense Eucalyptus camaldulensis Dehnh. aforested plots at the Kowsar Station is $32381. 00 per hectare with an annual mean of $925. 17 per hectare.

Estimating aquifer hydraulic parameters is essential for the assessment and management of groundwater resources. In this paper, the hydraulic parameters of Malekan Plain Aquifer were estimated using the resistivity data. The inverse electrical resistivity model to provide the best distribution of subsurface electrical resistance, using the inverse resistivity programs has been carried out. The relative thickness of subsurface layers using the characterization of electrical resistance curves was determined. The average thicknesse of, the alluvial aquifer and its porosity (ϕ ) and specific yield (Sy) were estimated at 75 meters, 0. 32 and 0. 042, respectively. Results indicate a strong correlation between aquifer transmissivity and the transverse presence of resistance. The estimated values from both geoelectrical and pumping test methods indicate that the results of electrical resistivity tomography method are acceptable. Therefore, using suitable results may be obtained a combination of pumping test, geological studies and geophysical methods. The aquifer parameters obtained from the resistivity sounding and pumping test data may be used for an optimal management and assessment of groundwater resources.

The Improvement and development of predictions in ungauged catchments require recognizing effective factors and understanding the interactions between different components of the catchments and hydrological response in different climatic zones. The most important factors affecting the flow duration curve (FDC) indices are precipitation and its characteristics. Since the flow duration curve represents the hydrologic response of watersheds, investigating and recognizing the effect of rainfall distribution on it can help to identify predictive factors for estimating the flow duration curve in ungauged catchments. The purpose of this study was to analyze the relationships between the number of rainy days and the indices FDC in the different climate zones of the country. Catchments of each climatic region were separated using the climate map of the country and overlapping it with the four-level border map of the watershed, and 314 hydrometric stations with the common period (1976– 2011) in six climatic zones were selected. Flow duration curve using daily stream flow data were extracted by the Hydro Office software (2015) and indices of Q2, Q5, Q10, Q15, Q20, Q50, Q75, and Q90 were selected. The average of rainy days for each catchment was calculated and the regression relations between the FDC indices and the average of the number of rainy days in different climatic regions were extracted and analyzed. The results showed that the correlation between the indices of the first part of FDC with the number of rainy days in all selected watersheds of climatic zones had a weak and unreliable relationship for prediction and estimation of FDC in the ungauged catchments. But the relationships for the end parts of FDC (Q75 and Q90), were strong. It is noteworthy that the average coefficient of determination for the low flow indices (Q75 and Q90) with the average annual rainy days in catchments of different climatic zones was approximately equal to 0. 66. This indicates the importance of the parameter of the number of rainy days as the predictor of the low flow indices associated with the end part of the FDC in different climatic zones. Therefore, it is suggested that the number of rainy days should be used as a predictive parameter for estimating the indices of the end section of FDC; its use for estimating other indices is not recommended.

One way to achieve sustainable development in arid and semi-arid areas is to construct underground dams due to the relatively high evaporation rate from surface waters in these areas. The Khorram Abad region was selected to identify suitable sites for constructing such dams using the hierarchical analysis method. Location criteria (reservoir axis, vegetative cover, climate and water) were determined using the geo-sampling techniques. The most suitable areas to construct the underground dams and coordinates of points were identified. The points and their prioritization for construction of the underground dam were assessed using expert opinion. The layer of each criterion was calculated using a wide-ranging hierarchical analysis model in locating the underground dams and assessing the merit of each layer. The layers were coordinated using the ArcGIS software. The results indicated that the hierarchical analysis is a method that highlights the importance of appropriate standards in site selection and emphasizes the qualitative criteria, where there are numerous criteria, and neglects the quantitative criteria.

The present study was planned to investigate and predict the landscape metrics on the Talar Watershed, the Province of Mazandaran. Land use/land cover (LULC) maps were produced using the support vector machine (SVM) algorithm for the years 1989, 2000, and 2014. The land change modeler (LCM) was applied for the prediction of LULC maps in different LULC change scenarios for 2030. Multi-layer Perceptron and the Markov chain methods were conducted for transition potential modelling and change prediction, respectively. Landscape metrics including the percentage of landscape (PLAND), the number of patches (NP), the edge density (ED), the patch density (PD), the largest patch index (LPI), the landscape shape index (LPI), the interspersion and juxtaposition index (IJI), and the perimeter-area fractal dimension (PAFRAC) were investigated and extracted using the Fragstats software in the studied years and the LULC change scenarios. Results demonstrated that the changes in the trend of PLAND, NP, ED, PD, LPI, and LSI were decreasing, and increasing in other land use systems during the considered years in forest, rangeland and another LULCs, respectively. Elevation, distance from forest, distance from rangeland areas, and the empirical likelihood of change were identified as the most important factors influencing the LULC change in the studied scenarios. Also, the average increase of NP was calculated at 43. 2, 8. 9, and 7. 9 percent in continuing the current LULC change, deforestation, and residential area development scenarios, respectively. Prioritization of different areas that require restoration with respect to the incorrect LULC changes, and determination and implementation of the precautionary and protective measures in the areas with change prediction based on the studied LULC change scenarios, as well as considering land use planning conditions to improve the health of Talar Watershed by managers and planners are recommended.